Travis Kalanick, the chief executive of global ride-hailing company Uber, has said he will step down from a council of business advisors to the White House, as major tech companies continue to protest President Trump’s executive order on immigration and refugee programs. The announcement is the latest in a series of critical responses to Mr. Trump’s executive orders, highlighting the tech industry’s difficult position as it tries to engage with Trump, while still advocating for immigration laws that support their employees.